Electromotor dynamic/stable stage parameter identification method based on stator resistance observer

Abstract

The invention discloses an electromotor dynamic / stable stage parameter identification method based on a stator resistance observer. For the parameter identification at a dynamic stage of an electromotor, a stator resistance T-S (Takagi-Sugeno) fuzzy observer is introduced to obtain an actually-measured value of stator resistance on the basis that the existing MRAS (Model Reference Adaptive System) method is still adopted, and dynamic correction is carried out on a rotating speed reference model and a resistance reference model according to the actually-measured value of the stator resistance; and for the parameter identification at a stable stage, the identification method for the rotating speed of a rotor is achieved by adopting the MRAS method and the stator resistance T-S fuzzy observer which are the same as those adopted in the parameter identification at the dynamic stage, and the identification method for the resistance of the rotor is achieved by adopting simple conversion. The electromotor dynamic / stable stage parameter identification method based on the stator resistance observer has the beneficial technical effects that the problem of inaccurate reference models is solved, the low-speed operating performance of the electromotor can be improved, the adoption of a current injection method is avoided, the current injection equipment is saved, the complexity of a system is lowered, the introduction of torque ripple is avoided, and the like.

Description

technical field [0001] The invention relates to an on-line identification technology of induction motor parameters without a speed sensor, in particular to an identification method of electric motor dynamic / steady state phase parameters based on a stator resistance observer. Background technique [0002] In sensorless vector control systems of induction motors, the model reference adaptive method (also called MRAS method) is widely used in sensorless AC speed control systems due to its simple principle, easy implementation and good stability. [0003] In the sensorless vector control system based on MRAS method, the identification of motor parameters can be divided into two parts: dynamic phase and steady state phase. Many methods for estimating motor parameters online explicitly or implicitly require the motor to be in a dynamic process. In actual operation, the motor flux is usually in a steady state for a long time, and it is difficult to obtain the motor parameters in t...

AI Technical Summary

Problems solved by technology

However, there are two problems in the above method: if the operating frequency of the motor is the same as or very close to the frequency of the injected current (1-3Hz), it will not only fail to meet the "full excitation" condition, but will cause the pulsating component of the injected current. Bring more torque ripple

Therefore, in the case of "the operating frequency is the same or very close to the frequency of the injected current", this method cannot be used; even if this method can solve the problem of "the operating frequency is the same or very close to the frequency of the injected current", due to the need to increase The corresponding injection current equipment not only increases the fault source, but also complicates the structure of the industrial application itself, which is not easy to realize

[0005]Secondly, when using the MRAS method to identify the rotor speed and rotor resistance, there is a problem in the identification accuracy: when the motor is working at a low speed, the rotor speed and rotor resistance The identification of rotor resistance is a difficult point, and it is also a current research hotspot

When the motor is running at low speed, the accuracy of speed estimation is quite sensitive to the model parameter error inside the motor. In the MRAS method, the reference model usually uses the voltage model as the standard model, and the voltage model contains stator resistance. During operation, the motor temperature The change of frequency will cause the stator resistance in the voltage model to change accordingly, which will bring errors to the voltage model, especially at low speed and close to zero speed, the measurement error will even submerge the back electromotive force, which will cause the speed and the accuracy of rotor resistance estimation during transients is greatly reduced, deteriorating the operating performance of the motor at low speeds

Images